Crank shaft



Feb. 23 1926.

C. L. WALKER CRANKSHAFT Filed April 26. 1924 lllllll h 2 Sheets-Sheet 1lNvzwi'on. CLINTONLWALKER.

Feb. 23 1926. 1,574,219

- C. L. WALKER CRANK. SHAFT Filed April 26. 1924 2 Sheets-Sheet 2 /N VENTOR.

CLINTONLMLKER. BY

4a ATTORNEYS.

Patented reazs, 926.

L. WALKER, 0F PIEDMONT, CALIFORNIA.

01mm: smr.

- n ncation filed April as,

To all whom it ma-y concern:

Be it known that I, CLINTON L. WALKER, a citizen of the United States,residing at Piedmont, county of Alameda, and State of California, haveinvented new and useful Improvements in Crank 'Shafts, of which thefollowing is a specification.

" This inventipn relates to a or: nk shaft,

and particularly to a four-throw crank shaft such as employed infour-cylinder interna combustion engines and the like. 1

The object of the present invention is to generally improve and sim lifythe construction and operation of crank shafts of thecharacterdescribed; to reduce and neutralize inertia forces caused byreciprocating .arts; to neutralize any inertia forces caused y the websand, crank pins of the shaft, and further, to so position the cranksthat excessive intermittent bearings pressures are materially reducedand a substantially uniform continuous bearing pressure obtained.-

For the purpose of clearly describing and illustrating the crank shaft,reference will be made to the accompanying specification and drawings,in which i Fig. 1 is aside elevation of the crank shaft.

Fig. 2 is an end'view of thesame. hliig. 3 is a diagrammatic view of thecrank, s a

Fig. 4 isa diagrammatic view showing a conventional form of four-throwcrank I i a I Fig. 5 is a diagram showing the inertia forces caused bythe reciprocating parts resolved into their vertical and horizontalcomponents. I

. Referring to the drawings in detail, and particularly toFigs. 1 and 2,it' will be noted .that the crank shaft illustrated employs threebearings, 'a center bearing L, and a pair of end bearings M and N. Thecrank shaft is otherwise provided with four crank pins, as indicatedat-A, B,-O and D, and these are supported withrelation to the shaft bymeans of webs such as illustrated at 3, 4, 5,6, 7 and 8. The crankpins,to-; gether with the webs supporting the same, are arranged on a commonplane; the cranks A and B being disp-osedopposite eachother or 180apart, the cranks B and 0 being similarly placed opposite eachother or180 apart, and the cranks G and D being also placed opposite each otherand therefore 18 0 apart. All adjacent cranks are for described.

1924. Serial 12,109,290.

FICE.

this reason opposed to each other and so are I cranks A and D, andsimilarly cranks B and 'O. This is exceedingly important as tlusparticular arrangement of the cranks permits substantial neutralizationof certain inertia forces and also reduces bearing pressures to aminimum, as will hereinafter be The shaft is 'otherwise provided withcounterweights as indicated atH, K-,'h and is; the lar to the crank webs3 .and 8' by means of straps and bolts indicated at 9 and 10,respectively, and the smaller counterweights h and 7c beingsecure'd tothe webs 4- and 7 by bolts as indicated at 11.

The method of positioning the counterweights and determining the weightof the same will; not be consideredin detail in the present applicationas it forms the subject-matter of my co-pending application entitledMethod of counterbalancing engine 'er counterweights H and K be- ,ingsecured main shafts, filed February 4,1924, Serial For the purpose ofclearly bringing out the advantags of a shaft constructed as heredescribed, reference will be made to the diagrammatic illustration of aconventional form of four-throw'crank shaft such as illustrated in Fig.4. Fig. 4 shows a threebearing four-throw shaft with the cranks set on acommon plane. This particular construction causes the crank pins 2, and3 to align and-similarly the crank pins l -and 4*. Crank pins lfband 2are opposed to each other and spaced 180 apart and -'so are the crankpins?) and P. It will, however, be. noted that'the cranks 2. and 3 areali ed and similarly the cranks 1" and 4. TlllS is objectionable asexcessive intermittent bearing pressures are exerted, particularly ,onthe center bearing indicated at 20, as crank pins 2 and 3 are alignedand as such travel in unison.

The combined inertia forces of the crank pistons connected therewith arethus im osed upon the center bearing in unison, and

1t is for this reason that the center bearing is subjected tounnecessarypressures. j I By referring to Fig. 3, which is a diagrammatic view ofthe shaft'forming the subject-matter of the present application, it'

will be noted that the crank pins 2 and 31" are oppos ed t o each otherand that due to this posltlomng of the plns inertia forces of I made toFig. 5, which is a dia the cranks, connecting rods and pistons are theinertia forces caused by t e reciprocating parts resolved into theirvertical and horizontal components. A predetermined condition will beconsidered: The diagram is developed from a four-cylinder Buick moltor,four and one-half inch cylinder diamreciprocating parts, to-wit, pistonand connectmg rod assembly, is approximately nine pounds for eachcylinder and the revolutions are 1800 R. P. M. A conventional shaft suchas illustrated in Fig. 4 was first tested. The inertia forces producedare illustrated by the line. W. By following this line it will be notedthat at the upper end of each stroke a maximum inertia force of 270ounds is reached, and at the lower end of t e stroke a maximumof,approximately 160 pounds pressure is reached. The second curved lineindicated at X was produced by employing a shaft such as shown in Figs.1 and B. The maximum inertia force produced during the upstroke wasapproximately pounds and the maximum -inertia force reached during" thedownward stroke was similarly approximately 50 pounds. The inertiaforces were 1 computed in connection with the center bearing in eachinstance and it certainly shows that a material reduction 1n bearingpressure is obtained when comparison is made between the. two shafts.

The results obtained with the shaft struc ture forming thesubject-matter of the present application are, a material reduction invibration due to the possibility of substantially neutralizing theinertia forces of reciprocating parts, and a uniform con-' tinuousbearing pressure.

While certain features of the presentinvention are more or lessspecifically illustrated, I wish it understoodthat various changes inform and proportion may be reeter by five inch stroke. .The weight ofthesorted to within the scope of the appended claims. I similarly wishit understood that the materials and finish of the several partsemployed may be such as'the experience and judgment of the manufacturermay dictate or various uses may demand.

Having thus described my. invention, what I claim; and desire to secureby Letters Patent is 1. A crank shaft provided with four cranks, a pairofend webs and intermediate .webs, the center cranks being set 180 apartand the end cranks being set 180 with relation to. the adjacent centercranks and 180 with relation to each other, and all cranks beingarranged on a common plane and said cranks being disposed in pairs, anda pair of counterweights one opposite to each endmost web and forming anextension of said webs.

2. A shaft of the character described, having a center bearing and apair of end bearings, two pairs of cranks formed on the shaft one pairon each si e of the center bearing, the cranks in each pair being set1809 apart and the adjacent center cranks 180 apart, and all cranksbeing arranged on a common plane, acentrally disposed.

web member connecting the cranks in each pair, a counterweight on eachof said webs, an end web on each end of the shaft, and a counterweighton each of said webs.

3. A crank shaft provided with four cranks, the center cranks being set180 apart and the end cranks being set 180 with relation to the adjacentcenter cranks, and 180 with relation to each other and all cranksbeingarranged on a common plane, said cranks being disposed in pairs, acentrally disposed web member connecting the cranks in each pair, acounterweight on each of said webs, and end bearings supporting theshaft.

4. A crank shaft provided -with four cranks, the icenter cranks beingset 180 apart and the end cranks being set 180 with relation to the.adjacent center cranks, and 180 with relation toeach other and allcranks being arran ed on a common plane, said cranks being isposed inpairs,'.a centrally disposed web member connecting the cranksin'eaclrpair, a counterweight on each of saidwebs, an'end web on eachend of the shaft, a counterweight on each of said webs, and an endbearmg connected with each' of said end webs.

CLINTON L. WALKER;

